So called patch insulin pumps and glucose monitors are attached to the surface of a subject. It is advantageous to minimize the weight of these pumps and monitors by using a control unit that is separate from the portion attached to the subject. If a wireless connection is made between the portion attached to the subject and the control unit it is critical that the connection be secure and impervious to attacks. Losing control of an insulin pump to a hacker could endanger the health of the person wearing the pump.